Semiconductor devices such as T-CSP (Tape-Chip Scale/Size Package) are known, which use a substrate on which an interconnect pattern is formed. Commonly, a semiconductor chip is mounted on the substrate, and with the electrodes of the semiconductor chip electrically connected to the interconnect pattern, solder balls are provided. The characteristics required of the surface of the interconnect pattern for connecting the electrodes of the semiconductor chip and the characteristics required for providing the solder balls are different. Although the surface of the interconnect pattern requires locally varying characteristics, conventionally the whole of the surface of the interconnect pattern has been subjected to a single plating operation.